I have an ASUS ROG, it's about 2-3 years old. I have no issues with it generally.

Lately when I turn it on it shows the "Republic of Gamers" logo screen for a second (as it should) and then the screen would suddenly appear either all vertical striped or one thin line around the top third of the screen, then after a second the screen would turn off. The computer might still seem like it's working but it would never actually turn on again. What I then do is press and hold the power button for a couple of seconds until it shuts off, and when I boot it up again - everything's fine.

This doesn't happen all the time, but maybe 70% of the time. The second time in a row I turn it on always works out fine.

It used to be pretty much constantly connected to the TV with an HDMI cable and I never turned it off, so I don't know when this issue might have started, and I've had trouble finding other people with similar issues.